System and process for electroslag additive manufacturing

Abstract

A method of forming a component using electroslag additive manufacturing includes supporting a base member for rotation about a longitudinal axis defined by the base member. The method also includes positioning an electroslag welding apparatus adjacent the base member, operating the electroslag welding apparatus, and rotating the base member about the longitudinal axis while operating the electroslag welding apparatus. The method also includes translating the electroslag welding apparatus along a first length of the base member while operating the electroslag welding apparatus and depositing with the electroslag welding apparatus a layer of material at a rate between 20 kg / hour and 300 kg / hour completely around the base member along the first length. The method also includes forming a disk on one of the layer of material and the base member by performing the steps of positioning the electroslag welding apparatus at a predetermined position along the longitudinal axis, rotating the base member about the longitudinal axis while operating the electroslag welding apparatus, and depositing with the electroslag welding apparatus sequential layers of material on top of one another at a rate between 20 kg / hour and 300 kg / hour completely around the base member until an outer most layer exceeds a predetermined diameter.

Description

SYSTEM AND PROCESS FOR ELECTROSLAG ADDITIVE MANUFACTURINGBACKGROUND

[0001] The manufacture of large components such as gas turbine or steam turbine rotors or casings often involves purchases of long-lead time raw materials. These raw materials may include rough forgings, castings, plate, or bar material. While additive manufacturing techniques for metal components are known, the deposition rates produced by these processes, and in some cases the material properties are not well-suited to manufacturing these large components.SUMMARY

[0002] In one construction, a method of forming a component using electroslag additive manufacturing includes supporting a base member for rotation about a longitudinal axis defined by the base member. The method also includes positioning an electroslag welding apparatus adjacent the base member, operating the electroslag welding apparatus, and rotating the base member about the longitudinal axis while operating the electroslag welding apparatus. The method also includes translating the electroslag welding apparatus along a first length of the base member while operating the electroslag welding apparatus and depositing with the electroslag welding apparatus a layer of material at a rate between 20 kg / hour and 300 kg / hour completely around the base member along the first length. The method also includes forming a disk on one of the layer of material and the base member by performing the steps of positioning the electroslag welding apparatus at a predetermined position along the longitudinal axis, rotating the base member about the longitudinal axis while operating the electroslag welding apparatus, and depositing with the electroslag welding apparatus sequential layers of material on top of one another at a rate between 20 kg / hour and 300 kg / hour completely around the base member until an outer most layer exceeds a predetermined diameter.

[0003] The method may also include the use of a cylindrical base member. The method may also include an electroslag welding apparatus that includes a consumable in the form of a strip, and where the consumable is deposited to form each of the layers of material.

[0004] The method may also include an electroslag welding apparatus that includes a flux delivery system operable to deliver a powdered flux during operation of the electroslag welding apparatus. The method may also include operating the electroslag welding apparatus at a deposition rate between 25 kg / hour and 50 kg / hour.

[0005] The method may also include forming a disk using a wire arc additive manufacturing process. The method may also include positioning a first chill member adjacent a first side of the disk during the formation of the disk. The method may also include further positioning a second chill member adjacent a second side of the disk during the formation of the disk. The method may also include positioning a core in a desired position with respect to the base member and where the layer of material covers at least a portion of the core. The method may also include removing the core from the layer of material to define a passageway.

[0006] Other technical features may be readily apparent to one skilled in the art from the following figures, descriptions, and claims.

[0007] In one aspect, a method of forming a component using electroslag additive manufacturing, includes supporting a planar base plate for rotation about a rotational axis that is normal to the planar base plate, positioning an electroslag welding apparatus adjacent the base plate, operating the electroslag welding apparatus, and rotating the base plate about the rotational axis while operating the electroslag welding apparatus to apply a first set of sequential layers of material on top of the base plate and on top of one another at a rate between 20 kg / hour and 300 kg / hour until a first final layer exceeds a first predetermined height above the base plate to define a first flange. The method also includes rotating the base plate about the longitudinal axis while operating the electroslag welding apparatus to apply a second set of sequential layers of material on top of the first final layer and on top of one another until a second final layer exceeds a second predetermined height above the base plate to define a wall having a wall thickness. The method further includes positioning a backing plate on the wall, the backing plate including a surface that is positioned coplanar with the second final layer, and rotating the base plate about the longitudinal axis while operating theelectroslag welding apparatus to apply a third set of sequential layers of material on top of the backing plate, the second final layer, and one another at a rate between 20 kg / hour and 300 kg / hour until a third final layer exceeds a third predetermined height above the base plate to define a second flange.

[0008] The method may also include where the electroslag welding apparatus includes a consumable in the form of a strip, and where the consumable is deposited to form each of the layers of material. The method may also include where the electroslag additive manufacturing includes a flux delivery system operable to deliver a powdered flux during operation of the electroslag welding apparatus. The method may also include where the deposition rate of the electroslag welding apparatus is between 25 kg / hour and 50 kg / hour. The method may also include forming a detail feature using a wire arc additive manufacturing process. The method may also include where a distance between the first final layer and the second final layer is between 10 and 500 times the wall thickness. The method may also include using a base plate and a backing plate that are each annular. The method may also include positioning a core in a desired position with respect to the base plate and where one of the layers of material covers at least a portion of the core. The method may also include removing the core from the layer of material to define a passageway.

[0009] Other technical features may be readily apparent to one skilled in the art from the following figures, descriptions, and claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0010] To easily identify the discussion of any particular element or act, the most significant digit or digits in a reference number refer to the figure number in which that element is first introduced.

[0011] FIG. 1 schematically illustrates a system arranged to perform electroslag additive manufacturing.

[0012] FIG. 2A schematically illustrates a side view of a cylindrical base member suitable for use in forming a component using electroslag additive manufacturing.

[0013] FIG. 2B schematically illustrates an end view of the base member of FIG. 2A.

[0014] FIG. 3A schematically illustrates a side view of the component following a first electroslag additive manufacturing step.

[0015] FIG. 3B schematically illustrates an end view of the component of FIG. 3 A.

[0016] FIG. 4A schematically illustrates a side view of the component following a second electroslag additive manufacturing step.

[0017] FIG. 4B schematically illustrates an end view of the component of FIG. 4A.

[0018] FIG. 5A schematically illustrates a first step in an electroslag additive manufacturing process for manufacturing a second component.

[0019] FIG. 5B schematically illustrates a second step in the electroslag additive manufacturing process for manufacturing the second component.

[0020] FIG. 5C schematically illustrates a third step in the electroslag additive manufacturing process for manufacturing the second component.

[0021] FIG. 5D schematically illustrates a fourth step in the electroslag additive manufacturing process for manufacturing the second component.

[0022] FIG. 6 schematically illustrates a top view of an electroslag additive manufacturing system applying material to the component.

[0023] FIG. 7 schematically illustrates a section view of the electroslag additive manufacturing system and component of FIG. 6 taken along line 7-7.

[0024] FIG. 8 schematically illustrates a top view of the arrangement of FIG. 6 and further including a core.

[0025] FIG. 9 schematically illustrates a section view of the electroslag additive manufacturing device and component of FIG. 8 taken along line 9-9.DETAILED DESCRIPTION

[0026] Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in this description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

[0027] Various technologies that pertain to systems and methods will now be described with reference to the drawings, where like reference numerals represent like elements throughout. The drawings discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged apparatus. It is to be understood that functionality that is described as being carried out by certain system elements may be performed by multiple elements. Similarly, for instance, an element may be configured to perform functionality that is described as being carried out by multiple elements. The numerous innovative teachings of the present application will be described with reference to exemplary non-limiting embodiments.

[0028] It should be understood that the words or phrases used herein should be construed broadly, unless expressly limited in some examples. For example, the terms “including,” “having,” and “comprising,” as well as derivatives thereof, mean inclusion without limitation. The singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Further, the term “and / or” as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. The term “or” is inclusive, meaning and / or, unless the context clearly indicates otherwise. The phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like. Furthermore, while multiple embodiments or constructions may be described herein, anyfeatures, methods, steps, components, etc. described with regard to one embodiment are equally applicable to other embodiments absent a specific statement to the contrary.

[0029] Also, terms such as “first”, “second”, “third” and so forth may be used herein to refer to various elements, information, functions, or acts, but should not be considered as limiting in any way. Rather these numeral adjectives are used to distinguish different elements, information, functions or acts from each other. For example, a first element, information, function, or act could be termed a second element, information, function, or act, and, similarly, a second element, information, function, or act could be termed a first element, information, function, or act, without departing from the scope of the present disclosure.

[0030] In addition, the term “adjacent to” may mean that an element is relatively near to but not in contact with a further element or that the element is in contact with the further portion unless the context clearly indicates otherwise. Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise. Terms “about” or “substantially” or like terms are intended to cover variations in a value that are within normal industry manufacturing tolerances for that dimension. If no industry standard is available, a variation of twenty percent would fall within the meaning of these terms unless otherwise stated.

[0031] FIG. 1 illustrates an electroslag welding apparatus 100 suitable for use in electroslag additive manufacturing. Electroslag welding (ESW) is a welding process primarily used for joining thick sections of metal. It is particularly well-suited for materials such as steel and stainless steel, where thick section and high-quality welds are crucial. In electroslag welding, a consumable 106 or electrode is fed into the joint between the workpieces to be welded. The electrode, typically a bare metal wire or a metal-coated flux-cored wire, is positioned above the joint. The workpieces may be preheated to a temperature suitable for the welding process. The welding process begins by initiating an electrical current between the electrode and the workpieces to form an electrical circuit. The resistance between the electrode and the workpieces generates heat, which melts the electrode tip, flux, and the base metal at the joint interface, creating a molten pool. As the molten metal pool forms, it is protected from atmospheric contamination by a layer of flux that covers the weld zone. The flux is added continuously or periodically and acts as both a heat conductor and a chemical agent, promoting the formation of a stable arc and aiding in the exclusion of impurities from the weld. The heatgenerated by the electrical current and the melting of the electrode and flux causes the molten metal pool to rise upward along the joint, pushing excess slag and impurities to the surface and eventually extinguishing the arc. Once the arc is extinguished, heat continues to be added by electrical resistance through the molten slag and as current flows through the molten pool of metal. The molten slag, a combination of the flux and melted electrode material, solidifies above the joint as it cools. This solidified slag layer acts as a barrier, trapping the heat and maintaining the high temperature in the weld pool necessary for achieving complete fusion.The process continues until the desired weld depth is achieved. The continuous addition of flux and the gradual upward movement of the weld pool result in a continuous, fully fused weld deposit.

[0032] The electroslag welding apparatus 100 of FIG. 1 includes two drive rolls 102, two contacts 104, a consumable 106, and a flux delivery system 108. The drive rolls 102 are selected based on the shape of the consumable 106 and are typically cylindrical or disk-shaped. The drive rolls 102 are arranged to frictionally engage the consumable 106 to draw consumable 106 from a feed source and deliver it to a weld location 124. The arrangement of the drive rolls 102 is not critical with many different arrangements being possible and suitable for use.

[0033] In the illustrated construction, the consumable 106 is a strip or sheet material. It therefore has a rectangular cross section having a long side and a short side. The long side is selected to at least partially define a width of a layer of material 120 created during the welding process with the size of the short side selected to facilitate proper melting and deposition rates. In other constructions, consumables 106 having different shaped cross-sections including square, circular, elliptical, etc. may be employed.

[0034] The contacts 104 engage the consumable 106 and are used to establish an electrical circuit that facilitates the welding process. To assure a good connection, the contacts 104 closely engage the consumable 106 and may also operate as a guide in some constructions. As with the drive rolls 102, the arrangement and positioning of the contacts 104 is not critical with many different variations being possible.

[0035] The flux delivery system 108 is arranged to deliver flux, and in the illustrated construction, a powdered flux 110 to the weld location 124. The flux delivery system typically includes components such as hoppers, feeders, flow lines and the like that can be positioned todeliver the powdered flux 110 to the desired location, at a desired rate. Again, the arrangement of the flux delivery system 108 is not critical with many variations being possible. In addition, powdered fluxes 110 are not the sole option available for flux with other arrangements using gasses, such as electrogas welding (EGW), or gasses in combination with powdered flux 110.

[0036] The electroslag welding apparatus 100 operates to form a layer of material 120 that has a desired width, depth, and length. The electroslag welding process allows for very wide layers of material 120 with the width at least partially controlled by the selection of the consumable 106. The depth of the layer of material 120 is selected based on feed speeds of the consumable 106 as well as movement of the weld location 124 via movement of the electroslag welding apparatus 100 and / or the base plate 122 with respect to one another. Weld depths are typically selectable between 1 and 15 millimeters with lower or higher depths being possible.

[0037] As the welding process proceeds, the tip of the consumable 106 and a portion of the base plate 122 or the layer of material 120 upon which the weld is being placed melt to form a weld pool containing molten metal 116. In addition, a portion of the powdered flux 110 melts. The components of the powdered flux 110 that melt move to the top of the molten metal 116 (i.e., the interface between the atmosphere and the molten metal 116) to form a layer of molten slag 112. It should be noted that the powdered flux 110 may also include alloying metals or components that melt or mix with the molten metal 116 rather than moving to the layer of molten slag 112. The molten slag 112 covers the molten metal 116 to protect it from oxidation and to retain heat.

[0038] As the base plate 122 moves in a direction of movement 126 (or the electroslag welding apparatus 100 moves in the opposite direction) the weld location 124 moves away from the molten metal 116 and the molten slag 112, thereby reducing the heat input in those areas and allowing them to cool and solidify. The cooling molten metal 116 forms a solidified metal 118 and the cooling molten slag 112 forms a layer of solidified slag 114. The solidified slag 114 is eventually removed to expose the solidified metal 118 which defines a portion of the layer of material 120. The movement of the base plate 122 in the direction of movement 126 defines the length of the weld being made.

[0039] The use of the electroslag welding process rather than other processes allows for a lower-energy per mass of metal deposited process that can produce welds with much greaterthicknesses. In addition, a single electroslag welding apparatus 100 can operate to produce deposition rates between 20 kg / hour and 300 kg / hour with even greater deposition rates being conceivable. Preferred deposition rates generally fall between 25 kg / hour and 50 kg / hour for each electroslag welding apparatus 100. In some arrangements, multiple electroslag welding apparatus 100 may be employed to greatly increase the overall deposition rate.

[0040] The electroslag welding process with these high deposition rates is therefore suitable for use as an additive manufacturing process for large industrial components. Examples of these components include but are not limited to rotors, such as gas or steam turbine rotors, generator rotors, compressor rotors and the like. In addition, large casings, housings, or other components could be additively manufactured using the electroslag welding apparatus 100 of FIG. 1 alone or in combination with other processes such as wire arc additive manufacturing processes. The near net shape produced would then require minimal machining to complete a product with greatly reduced lead times and costs as compared to conventional manufacturing processes.

[0041] FIG. 2A through FIG. 4B illustrate a component in the form of a rotor 400 and method for manufacturing the rotor 400 using an electroslag additive manufacturing process.

[0042] In the illustrated method, the process begins with a base member 202 shown in FIG. 2A and FIG. 2B. The base member 202 of FIG. 2A is cylindrical and defines an outer diameter and a longitudinal axis 204. In some constructions, the cross-section of the base member 202 is circular with other constructions having an annular shape such that a bore is formed along a portion or the full length of the base member 202 along the longitudinal axis 204.

[0043] For some components, such as a turbine rotor 400 or a generator rotor 400 the base member 202 includes a bore and is forged with a desired wall thickness. The wall thickness may be selected to assure certain high-stress areas are part of the forging. In addition, the forging can be inspected using x-ray, ultrasonic or other technologies to verify a desired level of quality. Additionally, the wall thickness and shape of the base member 202 may be selected to allow for the base member 202 to be used to manufacture multiple rotors 400 of different designs while still allowing reduced lead times for the base member 202.

[0044] One or more layers of material 120 are added to a portion or the full length of the base member 202 as illustrated in FIG. 3 A and FIG. 3B. The layers of material 120 are added usingthe electroslag welding apparatus 100 of FIG. 1 and the process discussed with regard to FIG.1.

[0045] The number of layers and the thickness of each layer of material 120 may be selected to achieve the desired outside diameter of the layers of material 120 while also allowing for periodic inspection if desired. For example, inspection of each 15 mm of material may be required. In such a circumstance, each layer of material 120 may be selected to be about 12 mm, thereby assuring adequate inspection. The thickness of each layer of material 120 may also be selected to assure the desired material properties and weld quality.

[0046] The final step in the formation of the rotor 400 involves the additive manufacturing addition of one or more disks 402 and one or more narrow disks 404 as may be necessary for the particular design. Of course, some designs may not include any disks 402 or narrow disks 404.

[0047] Each disk 402 is formed by the placement of one or more layers of material 120 using the electroslag welding apparatus 100 of FIG. 1. The width of each layer of material may be selected to require only a single pass to form each layer of material 120 depending on the desired final width of the disk 402. As will be discussed in greater detail with regard to FIG. 6 through FIG. 9, chill members 602 may be employed to complete one or more of the disks 402 to provide for sides that are nearer to the final desired size and shape. As one of ordinary skill will understand, other features of the rotor 400 or other component could be added to the rotor 400 or other component using the electroslag process and the electroslag welding apparatus 100 illustrated in FIG. 1.

[0048] Other processes, such as wire arc additive manufacturing processes could also be employed in conjunction with or in place of electroslag additive manufacturing to complete additional features or components that are not as well-suited to the electroslag process. One example of such a feature are the narrow disks 404 illustrated in FIG. 4A. The narrowness of the narrow disks 404 makes another process such as a wire arc additive manufacturing process better suited to forming these features.

[0049] Wire Arc Additive Manufacturing (WAAM) is a production process used to 3D print or repair metal parts. It belongs to the Direct Energy Deposition (DED) family of additive manufacturing processes. WAAM is executed by depositing layers of metal on top of eachother, until a desired 3D shape is created. It is a combination of two production processes: Gas Metal Arc Welding (GMAW) and additive manufacturing. GMAW is a welding process used for joining metal parts using an electric arc, and additive manufacturing is the industrial term for 3D printing.

[0050] As one of ordinary skill will realize, the use of multiple processes, including electroslag additive manufacturing allows for the manufacture of many different components such as the rotor 400 with greatly reduced lead times and costs. The rotors 400 may include any number of features including, but not limited to the disks 402 and the narrow disks 404 illustrated in FIG. 4A and FIG. 4B. In addition, the simultaneous use of multiple electroslag welding apparatus 100 could greatly increase the overall deposition rate as may be desired.

[0051] FIG. 5A through FIG. 5D illustrate another component in the form of a casing 500 that is well-suited to being manufactured using an electroslag additive manufacturing process and the electroslag welding apparatus 100 of FIG. 1. The rotor 400 of FIG. 4A is manufactured while rotating the component about a horizontal longitudinal axis 204 to allow the electroslag welding apparatus 100 to be positioned to weld downward or in a 1G position. While not strictly required for electroslag welding, welding in the 1G position generally provides high- quality welds and is preferred when possible.

[0052] In contrast, the casing 500 of FIG. 5D is manufactured using the same electroslag additive manufacturing process and the same electroslag welding apparatus 100 but with the component rotating about a rotational axis 514 that is arranged vertically. Again, this allows for welding in the 1G position but leads to the component being built up in length along the rotational axis 514, rather than being built-up in diameter with respect to the longitudinal axis 204.

[0053] The process for manufacturing the casing 500 begins by positioning a base plate 502 for rotation about the rotational axis 514. The base plate 502 is substantially planar with the rotational axis 514 being normal to the plane of the base plate 502. The base plate 502 may be a solid plate or may include gaps or apertures in locations where no material or layers will be added. For example, in the illustrated construction, an annular base plate 502 may be suitable for use.

[0054] Next, layers of material 120 are placed on the base plate 502 to form a first flange 504. Specifically, a first set of sequential layers of material is applied to the base plate 502 until a first predetermined height is reached. In the illustrated construction, the first flange 504 is annular in shape and has a flange width and a flange thickness or height. The flange thickness, measured from the base plate 122 to a first final layer and width can vary greatly, thereby allowing for the manufacture of any number and shape of first flange 504. In addition, as will be discussed in greater detail, holes such as bolt holes could be pre-formed in the first flange 504.

[0055] Turning to FIG. 5B, a wall 506 is next formed on top of the first flange 504. Specifically, a second set of sequential layers of material is applied on top of the first final layer until a second final layer at a second predetermined height is reached. The wall 506 for the casing 500 is a thin wall 506 meaning that the length or height of the wall 506 is on the order of 10 to 500 times longer than the thickness of the wall 506. Of course, walls 506 having different length to thickness ratios can also be produced as described herein. In the construction of FIG. 5B, the wall 506 is annular and frustoconical or tapered. Other constructions could include a wall that tapers outward, rather than inward or could include a cylindrical shaped wall.

[0056] Still other constructions could form the wall 506 in other geometric shapes such as rectangular or polygon shapes. In these constructions, the base plate 502 may need to be supported for both rotation about the rotational axis 514 as well as translation normal to the rotational axis 514. Alternatively, the base plate 502 could be supported for rotation and the electroslag welding apparatus 100 could be arranged to move linearly to allow for the formation of polygonal-shaped walls 506. Thus, the system illustrated herein could form walls 506 of virtually any shape desired.

[0057] In order to add a second flange 510 to the top of the wall 506, a backing plate 508 must first be positioned adjacent the top surface of the wall 506. Specifically, the backing plate 508 is an annular plate having an inside diameter sized to fit over the outside diameter of the wall 506 such that a top surface of the backing plate 508 is substantially coplanar with the second final layer of the wall 506. Thus, the top of the wall 506 and the top surface of the backing plate 508 define a surface upon which additional layers of material 120 can be applied using the electroslag welding apparatus 100 to form the second flange 510. Specifically, athird set of sequential layers of material is added to the second final layer and the top surface of the backing plate 508 until a third predetermined height is reached, thereby defining a third final layer. In some constructions, the backing plate 508 may be welded to the wall 506 using any available welding process, including electroslag welding, prior to the electroslag additive manufacturing process being used to form the second flange 510. In still other constructions, the backing plate 508 may be removed by a machining step after the final additive manufacturing step.

[0058] FIG. 5D illustrates the second flange 510 formed on top of the wall 506 and the backing plate 508. The second flange 510 is annular and has a second flange thickness and width that are selected for the particular design. As with the first flange 504, features such as bolt holes could be pre-formed as part of the second flange 510 during the electroslag additive manufacturing process.

[0059] To complete the manufacture of the casing 500, electroslag additive manufacturing or other additive manufacturing processes such as wire arc additive manufacturing processes, or standard assembly techniques may be employed to add detail features 512. For example, lifting lugs, connection flanges, or other features may be attached using standard welding techniques or formed using the aforementioned additive manufacturing techniques.

[0060] FIG. 6 and FIG. 7 illustrate the use of chill members 602 to form channels 604, slots 606, and other openings or voids in the layers of material 120 being added. Each chill member 602 is formed from a material having a higher melting point then the material being used to form the layer of material 120. High-temperature ceramics are a suitable choice for the formation of the chill members 602. In other systems, copper chill members 602 using cooling, such as water cooling are employed. Each chill member 602 is sized to create the desired void and in some cases can be moved to form elongated channels 604 or slots 606.

[0061] As shown in FIG. 6, the channel 604 is formed by positioning a chill member 602 a desired distance from the consumable 106. As the molten metal 116 solidifies, the chill member 602 blocks it from filling the space occupied by the chill member 602. The chill member 602 may be moved with the consumable 106 in the direction of travel 608 to form the channel 604 which may extend for a portion of the length of the layer of material 120 or may extend the full length.

[0062] Slots 606 are formed by positioning chill members 602 in positions that are generally fixed with respect to the base member 202 or the base plate 502. The chill members 602 may however move in directions that are normal to the direction of travel 608. Slots 606 may extend through multiple layers of material 120 and may vary in depth (into and out of the plane of FIG. 7) into the various layers of material 120.

[0063] Because electroslag welding does not rely on the maintenance of an arc, the consumable 106 can pass directly over a chill member 602 without disrupting fusion adjacent the chill or negatively affecting the material properties or quality of the layer of material 120.

[0064] While FIG. 6 and FIG. 7 illustrate two examples of the use of chill members 602, many other uses and arrangements are possible, and the process should not be limited to these examples. For example, a narrow layer of material 120 may be formed by positioning two chill members 602 parallel to one another to define a narrow space therebetween for the placement of the molten metal 116.

[0065] In another example, cylindrical chill members, or any other shape are used to pre-form bolt holes or other apertures in a component being manufactured.

[0066] FIG. 8 and FIG. 9 illustrate another variation of a chill member 602, in the form of a core 802 positioned in a layer of material 120. The core 802 has a circular cross section as illustrated in FIG. 9, with other cross-sectional shapes being suitable for use as well. The core 802 includes multiple connected legs that define a desired opening to be formed in one or more layers of material 120. As with the chill members 602, the core 802 is formed from a material that has a higher melting point than the material used to form the layer of material 120. One suitable material would include high-temperature ceramics, with other materials being possible.

[0067] As the consumable passes over the core 802, molten metal 116 and molten slag 112 are deposited without the core 802 interfering in the process. The molten metal 116 solidifies around the core 802 such that upon removal of the core 802, such as by chemical dissolution, a flow path or void that matches the shape of the core 802 is left in the layer of material 120. Virtually any shape core 802, or cross-section for a core 802 may be employed and as such do not limit the electroslag additive manufacturing process in any way.

[0068] In operation, the base member 202 or base plate 122, 502 is positioned and supported for the desired rotation and / or translation. The electroslag welding apparatus 100 is positioned adjacent the base plate 122, 502 or the base member 202 and the consumable 106 is fed toward the base plate 122, 502 or the base member 202. An arc is initiated that begins melting the consumable 106 to form a pool of molten metal 116. The consumable 106 is fed into the molten metal 116 until the arc is extinguished. However, electrical current continues to flow through the molten metal 116 such that the consumable 106 continues to melt and add metal and slag to the pool of molten metal 116. The molten slag 112 floats or moves to the surface of the molten metal 116 and inhibits the entry of unwanted oxygen or other components and retains heat to aid in maintaining the pool of molten metal 116. As the component being formed moves with respect to the consumable 106 (or the consumable 106 moves or both) a layer of material 120 is formed. This process continues until the desired final product (e.g., rotor 400, casing 500, etc.) is formed. As one of ordinary skill in the art will understand, any solidified slag 114 must be removed from a layer of material 120 prior to the addition of another layer of material 120.

[0069] The final product would then require some additional work to form the completed product. However, the ability of the electroslag additive manufacturing process to add material at very high deposition rates (e.g., between 20 and 300 kg / hour) results in reduced lead times and costs for the final component. In addition, for large components, it may be possible to use multiple electroslag welding apparatus 100 simultaneously, thereby greatly increasing the deposition rate and further reducing the time required to produce the component.

[0070] Although an exemplary embodiment of the present disclosure has been described in detail, those skilled in the art will understand that various changes, substitutions, variations, and improvements disclosed herein may be made without departing from the spirit and scope of the disclosure in its broadest form.

[0071] None of the description in the present application should be read as implying that any particular element, step, act, or function is an essential element, which must be included in the claim scope: the scope of patented subject matter is defined only by the allowed claims. Moreover, none of these claims are intended to invoke a means plus function claim construction unless the exact words "means for" are followed by a participle.

Claims

CLAIMSWhat is claimed is:

1. A method of forming a component using electroslag additive manufacturing, the method comprising: supporting a base member for rotation about a longitudinal axis defined by the base member; positioning an electroslag welding apparatus adjacent the base member; operating the electroslag welding apparatus; rotating the base member about the longitudinal axis while operating the electroslag welding apparatus; translating the electroslag welding apparatus along a first length of the base member while operating the electroslag welding apparatus; depositing with the electroslag welding apparatus a layer of material at a rate between 20 kg / hour and 300 kg / hour completely around the base member along the first length; and forming a disk on one of the layer of material and the base member by performing the steps of: positioning the electroslag welding apparatus at a predetermined position along the longitudinal axis; rotating the base member about the longitudinal axis while operating the electroslag welding apparatus; and depositing with the electroslag welding apparatus sequential layers of material on top of one another at a rate between 20 kg / hour and 300 kg / hour completely around the base member until an outer most layer exceeds a predetermined diameter.

2. The method of claim 1, wherein the base member is cylindrical.

3. The method of claim 1, wherein the electroslag welding apparatus includes a consumable in the form of a strip, and wherein the consumable is deposited to form each of the layers of material.

4. The method of claim 1, wherein the electroslag welding apparatus includes a flux delivery system operable to deliver a powdered flux during operation of the electroslag welding apparatus.

5. The method of claim 1, wherein the deposition rate of the electroslag welding apparatus is between 25 kg / hour and 50 kg / hour.

6. The method of claim 1, further comprising forming a disk using a wire arc additive manufacturing process.

7. The method of claim 1, further comprising positioning a first chill member adjacent a first side of the disk during the formation of the disk.

8. The method of claim 7, further comprising positioning a second chill member adjacent a second side of the disk during the formation of the disk.

9. The method of claim 1, further comprising positioning a core in a desired position with respect to the base member and wherein the layer of material covers at least a portion of the core.

10. The method of claim 9, wherein the method further comprises removing the core from the layer of material to define a passageway.

11. A method of forming a component using electroslag additive manufacturing, the method comprising: supporting a planar base plate for rotation about a rotational axis that is normal to the planar base plate; positioning an electroslag welding apparatus adjacent the base plate; operating the electroslag welding apparatus; rotating the base plate about the rotational axis while operating the electroslag welding apparatus to apply a first set of sequential layers of material on top of the base plate and on top of one another at a rate between 20 kg / hour and 300 kg / hour until a first final layer exceeds a first predetermined height above the base plate to define a first flange; rotating the base plate about the longitudinal axis while operating the electroslag welding apparatus to apply a second set of sequential layers of material on top of the first final layer and on top of one another until a second final layer exceeds a second predetermined height above the base plate to define a wall having a wall thickness; positioning a backing plate on the wall, the backing plate including a surface that is positioned coplanar with the second final layer; and rotating the base plate about the longitudinal axis while operating the electroslag welding apparatus to apply a third set of sequential layers of material on top of the backing plate, the second final layer, and one another at a rate between 20 kg / hour and 300 kg / hour until a third final layer exceeds a third predetermined height above the base plate to define a second flange.

12. The method of claim 11, wherein the electroslag welding apparatus includes a consumable in the form of a strip, and wherein the consumable is deposited to form each of the layers of material.

13. The method of claim 11, wherein the electroslag welding apparatus includes a flux delivery system operable to deliver a powdered flux during operation of the electroslag welding apparatus.

14. The method of claim 11 , wherein the deposition rate of the electroslag welding apparatus is between 25 kg / hour and 50 kg / hour.

15. The method of claim 11, further comprising forming a detail feature using a wire arc additive manufacturing process.

16. The method of claim 11, wherein a distance between the first final layer and the second final layer is between 10 and 500 times the wall thickness.

17. The method of claim 16, wherein the base plate and the backing plate are each annular.

18. The method of claim 11, further comprising positioning a core in a desired position with respect to the base plate and wherein one of the layers of material covers at least a portion of the core.

19. The method of claim 18, wherein the method further comprises removing the core from the layer of material to define a passageway.

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